When handling a plurality of modular parts it is often necessary to ensure that modular parts are not connected to one another in a prohibited manner. If for example electrical connections are to be provided between the modular parts, an incorrect joining together can cause defective operation of the modular part or even destruction thereof. The modular parts can be customized by the use of a coding, so that joining together in a prohibited manner is prevented.
It is known from U.S. Pat. No. 4,595,250 to provide a coding in the form of rotatable elements which have projecting fingers on one modular part and corresponding openings on the other modular part. This type of coding makes the structure relatively complicated, since it has to be constructed differently for the two modular parts and special provisions must be made which on the one hand enable the elements to be rotated if required, but which on the other hand prevent the elements from being moved inadvertently out of a defined rotated position.
It is known from U.S. Pat. No. 6,142,592 to provide a coding in the form of recesses on the modular parts into which coding pins can be inserted. This type of coding has the disadvantage that the coding pins are formed as separate parts and therefore can be lost in some circumstances. If not all the openings are provided with a coding pin, there is a danger that the coding is no longer unambiguous and thus it is possible to join modular parts together in a prohibited manner.
It is known from U.S. Pat. No. 6,196,881 to provide a coding in the form of recesses on one modular part and movable sliders with pins on the other modular part. If the coding setting allows the joining together of the modular parts, the pins engage in the recesses.
This type of coding has the disadvantage of a limited adjustability, since the recesses on one modular part have to be provided already at the time of production, so that the positions thereof cannot be changed at a later stage.
It is known from DE 25 34 775 A1 to provide a coding in the form of projecting coding elements which consist of insertable lugs on one modular part and teeth which can be broken out on the other modular part. This type of coding also has the disadvantage of limited adjustability, since breaking out of a tooth can no longer be reversed.